Steel joint ductility: coupling effect in adjacent T‐stubs

Abstract
The reusability of structural elements is considered as one of the most promising strategies to reach the carbon neutrality of the civil engineering sector in 2050, as recommended in the Paris agreement. And the structural joints are identified as key elements to promote the demountability and reusability of structures. In addition, the joint components could be designed to act as ductile fuse elements in case of overloading, to protect the structural elements to be reused. But to achieve this objective, it requires to master the full behaviour law of the fuse components both in the elastic and plastic fields. The latter concern is particularly of importance in the tension zone of joints where ductile components in bending such as the end‐plates or angles, usually modelled as equivalent T‐stubs, could be activated.
The present paper highlights a newly identified coupling effect between adjacent T‐stubs, inducing a premature yielding of the stronger connected T‐stub and so possibly compromising the fuse role of the weakest one. In addition, this coupling effect also leads to a reduction of the resistance of the overall system. A review of the literature is first proposed before presenting physically the above‐mentioned coupling phenomenon. Afterwards, numerical simulations are conducted to identify the parameters governing and influencing the new identified failure mode. Lastly, real case examples including the coupling effect are covered to highlight the major outcomes and practical design applications.